Heretofore, an encryption device adopting a secret key encryption method or a public key encryption method is designed to create encrypted identification information by performing prescribed encryption on identification by using encryption key information being stored in an internal non-volatile memory and send this to a decryption device.
In this case, the encryption device ensures reliability of an encryption function by preventing encryption key information being stored in the non-volatile memory from being stolen. As a method of preventing the encryption key information from being stolen, a non-volatile memory is installed between units at a deep part of the encryption device, or a non-volatile memory and an encryption/decryption unit for encrypting encryption key information only when the information is stored in the non-volatile memory are installed as one tip (for example, refer to Patent Reference 1).
Patent Reference 1 Japanese Patent Laid-open No. 2003-256282
However, such an encryption device is not enough to offer reliability of an encryption function because not only installation of a non-volatile memory is complicated but also encryption key information cannot be prevented from being stolen from the non-volatile memory.
This invention has been made in view of foregoing and proposes an encryption device and encryption method capable of improving reliability of an encryption function.
To solve the above problem, this invention provides an encryption device for encrypting information on a confidential target with: a creation means for creating a unique parameter of an element group, based on a signal output from the element group internally having a plurality of elements as a unit; and an encryption means for encrypting information by using the unique parameter created by the creation means.
Further, this invention provides an encryption method of encrypting information on a confidential target with: a first step of creating a unique parameter of an element group, based on a signal output from the element group internally having a plurality of elements as a unit; and a second step of encrypting information by using the created unique parameter.
As described above, according to this invention, information is encrypted by using a unique parameter of an internal element group. This means that encryption can be performed by using a unique parameter that third parties cannot detect, even in manufacturing, without previously storing the parameter in a non-volatile memory or the like, thereby being capable of easily ensuring confidentiality of identification information D1 and thus improving reliability of an encryption function.